1. Field of the Invention
Generally, in cultivation of the microorganisms, it is possible to know the cell density of microbes in the culture solution by measuring the optical density of the solution, so that it is of great consequence in the microbial industry to make accurate measurement of the optical density of the culture solution.
However, in culturing aerobic microorganisms, air bubbles are produced in great quantities in the agitation tank as air agitation is conducted therein, so that in measuring the optical density of a test solution by the colorimeter, said air bubbles often enter into the measuring chamber to excessively affect the light transmission rate owing to irregular reflection caused by such air bubbles, resulting in inaccurate measurement.
The present invention is to provide a colorimeter which permits accurate, easy and continuous measuring of the optical density of the solution to be examined by removing the air bubbles from the solution.
2. Description of the Prior Art
The basic mechanism of the colorimeter used in the present invention is preferably of the type which has been previously proposed by this inventor, but it is possible to use other types if they are capable of providing the same effects. The said previously proposed colorimeter is of the type in which the colorimeter is dropped into the solution to be checked so as to detect the optical density of the solution with ease from the photoelectromotive force indicated by a voltmeter connected to a photocell by a cable. Briefly, this type of colorimeter is constructed as follows. Light is projected from a light source through a color filter and a lens to a specimen chamber designed to allow free ingress and egress of the specimen (solution to be examined) so as to pass light from said light source through said specimen and to a photocell or phototransistor, said light source and photocell or phototransistor being respectively connected by a cable to a power source and a voltmeter which automatically records the absorbance.